Two-way PA speaker for a band...

[waxx]

Iron core coils can be used, but it's hard to find those who can handle such a powerlevel. Maybe it's better to go to transistor core coils, they will be a bit cheaper, but still a lot of money. The disadvantage is that you have a reverse flux, wich has an influence on the sound.

And 1.2kHz is too close to the resonance frequency of the woofer to be used for me. I would do the crossover lower (500-900Hz) with this drivers.

 

[kipman725]

I wind my own air coils by hand it takes ages but is cheap enough to be worthwhile on one off basis. I use a CD-R storage spindle with a nut and screw through the end of it to hold the wire on, I occasionally sand a section of wire while winding to measure the inductance, when I have the right value I remove the screw and slide the coil off. I then use four zip ties to hold the coil in shape and add lots of glue to hold the shape more rigidly. The resulting coils have a more random wind than a professionally produced one which means slightly less inductance for a given winding length and wire gauge. However they are cheap and I can get any value.

 

[Lojzek]

I used to wind the coils manually also until I remembered to have a device that would be the right thing to ease the work.

DIY Coil Winder

 

[Sven R]

Some thoughts and concerns, from someone that's been doing PA systems for a while:

- Ribbons don't like to be driven low or loud. The 1000w 200ms peak is something that the driver might (might) survive once. Or twice. The 60w continuous rating should be respected.
- You're going to need more than a pair of 12" midbass drivers to do the kick drum any justice, especially for the audience size you're talking about.
- The Crown amp you've chosen will leave performance on the table. If it was mine, I'd be looking for something that'd do >600w into 8ohm.


It's difficult for me to understand how you can confidently come up with all these specifications for your crossover, while being unable to design a crossover.

It seems to me like you need a consultant. Where are you located?
I have some ideas on what would make your speakers work well, but they are contrary to some of your ideas.

This is a job that'd take a few days to pull off well. First day would be spent with a measurement mic (and the cabinets built, with the drivers installed), and then perhaps half a day designing the crossover, and then order parts, and then build, test, and EQ the thing.

Studio-perfect sound can be achieved from a PA system. Mine usually do a pretty good job.

Chris

PS - On a different note, the best PA system in the world will sound pretty mediocre if your microphones etc aren't up to scratch.

Well, that is all like that... but, if I decided to give drums a real ¨field day¨, I would use a pair or two pairs of my bass horns, that are 1x15¨ bass horns, that go from 38 Hz low cut-off frequency to about 200 plus Hz! I have 16 of those bass horns - my own design, awesome. So, I got the ¨toys¨ for that kind of performance that you describe, but these two PA speakers, 2-way units consisting of 1x12¨and 1x ribbon H.F. are for more MODEST approach to playing in clubs, not very loud at all. If I would go loud, I would use these two speakers above 200 Hz, and my bass horns below 200 Hz, of course.

As for ribbons, yes, I agree, one must watch out... well, with sensitivity of about 107 dB/1W/1m, I really do not need to put more than 100 Watts on them, to make 107 plus 20 - equals 127 dB, which is much more than I ever need for a peak in a club where DIRECT FIELD is not longer than 10 meters (33 feet)! So, those ribbons are not going to get more than 100 Watts on them, peak, or a max. of 200 Watts (that is 23 dB, which combined with the above sensitivity makes a WHOPPING 130 dB!). So, do not worry about blowing H.F. units. But, just for the info, they ARE tested at 200 msec (ten times the industry standard of 20 ms for peak power!) to be capable of getting 1000 W. Well, as I stated, I do not need anything even remotely close to that, ever! THANKS FOR YOUR CONCERN AND KIND ADVICE!

 

[turk 182]

so what do you use for a x-over when your using your bass horns??


perhaps a mod should move this thread over to the PA section.

 

[AllenB]

the depth of the center .... is just about equal .... As for a breakup frequency being too close (half an octave)

Then if you make your low crossover high order, then the other should be high order as well. I have worked so close to breakup, it can be done.

It seems this is intended for pro use. A completed speaker from SA website.

 

[peterbrorsson]

The hen has an implant at least, however it's selbstbau

Rant off (topic)

cRAP, attachment disappeared, again...

Audio Selbstbau, Thel, Endstufen, Vorstufen, Aktivweichen, analoge Netzteile, Netzfilter

 

[EarlK]

How about modding a crossover already meant to work with the SA ( model ) 4547 ?

See this link!

The fact that even for studio control room applications SA uses a 24db/octave design ( at 1K with a 15: woofer ) should offer some insights into how to proceed.

Ditch the 12" for a 15" ( such as the JBL 2225 or the SA equivalent which is the SA1502 ) and you are away to the races.

See SA woofer bios on Facebook

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An externally hosted image should be here but it was not working when we last tested it.

See SA Blue Box Bio